也許你真的很中意那款淡粉色唇膏，可能你心愛的那支眼線筆才剛削去一小塊，但是，你有沒有想過，是時(shí)候該考慮新陳代謝了？沒有誰想讓自己心愛之物變成細(xì)菌的滋生地吧？一起來看一看各種化妝品的壽命吧！

Mascara? 睫毛膏
This is the makeup item you should be most vigilant about: As the brush is taken out, applied, and put back in the tube, it brings with it any bacteria that has collected along the way, explains cosmetic chemist Jim Hammer. Lingering bacteria can cause redness and itchiness, or even conjunctivitis (a.k.a. pinkeye) and sties. Switch mascara every two to three months to be safe. "It will also have a distinct gasoline-like smell once it's gone bad," says makeup artist Pati Dubroff. If you develop any negative symptoms, immediately throw out any of your eye makeup that may have been contaminated. If your eyes are still irritated a day or two later, see an eye doctor.
tips：刷子一進(jìn)一出，就會(huì)帶進(jìn)很多細(xì)菌。每?jī)扇齻€(gè)月更換一支睫毛膏最好。當(dāng)睫毛膏聞起來有汽油味的時(shí)候就說明壞了。

Foundation 粉底
With the exception of powder formulas, all foundations are water-based, which means bacteria love them. Unopened, foundation can last for a couple of years, but once the seal is broken, Hammer says, it's best to replace it after 6 to 12 months. Keep foundations out of moist environments (such as your bathroom) and away from heat, as high temperatures encourage the growth of the bugs and can speed up the spoiling—true for beauty products in general. An off smell or a change in color tells you the formula is finished—applying it could cause irritation or breakouts.
tips：粉底都含水，所以易滋生細(xì)菌。沒開封的粉底可保質(zhì)幾年時(shí)間，一旦拆封，6到12個(gè)月就該換了。變味和變色是粉底變質(zhì)的征兆。

Concealer 遮瑕膏
Concealers are meant to cover blemishes, not cause them—which is what can happen if you use a concealer that's too old. "You'll know it's gone bad because the color will start to shift," says cosmetic chemist Ni'Kita Wilson. Concealers in powder and stick form can last for up to two years, while liquids should be tossed after one.
tips：粉狀或棒狀的遮瑕可維持2年左右，液態(tài)遮瑕1年后就該更換。

Face Powder 散粉
Powders are the Energizer Bunny of makeup. They keep going...and going—at least, for up to two years. Still, as Wilson points out, "some powders contain small amounts of water from botanical extracts, so there's the risk of it growing bacteria if you leave it lying around your bathroom." Look on the ingredients panel for long Latin names—these are often botanicals, and their common names (such as oat extract, chamomile, aloe, bamboo, and green-tea extracts) are typically listed in parentheses.
tips：散粉可維持2年，但一些含植物精華的散粉不宜放在洗手間之類地方。

Eye Shadow 眼影
Eye-enhancing shadows? Yes, please. Eye-irritating ones? No, thanks. To keep your eyes from getting red or itchy, replace powder eye shadows after about three months, according to Hammer. Even though they are similar in formulation to other powders, because they're constantly in contact with a mucous membrane, there's a higher risk of transferring bacteria to the product and then back to the eyes. Pay extra attention to cream-based shadows, which tend to grow bacteria more quickly than powders. If you use your fingers to apply, wash your hands before doing so, and be aware of any color switches or off-putting smells.
tips：粉狀眼影3個(gè)月就該換了，膏狀眼影更容易滋生細(xì)菌

Eyeliner 眼線
Liquid or pencil, these eye definers should be replaced about every three months. Like eye shadows, they are applied near a sensitive area and can pick up bacteria and bring it back to the eye very easily "without any visible signs of contamination," Hammer warns. If you've used a dingy liner, you could experience redness, itchiness, or, in extreme cases, conjunctivitis. Pencils will last a bit longer than liquid if you're steadfast about regular sharpening, but you'll know they're dead once a white film starts to develop on the tip that can't be sharpened off, says Dubroff.
tips：眼線液，眼線筆和眼影一樣，每個(gè)月就該更換一次。相比之下，眼線筆比眼線液壽命長(zhǎng)一些。

Lipstick & Lip Gloss 唇膏唇彩
The wrong lipstick color may spoil your mood—but the risk of the formula spoiling (or growing bacteria) is low since they don't contain any water, says Hammer. But since they're repeatedly exposed to the mouth area, he suggests replacing lip products after a year, or if you've recently been sick. Lipsticks and lip glosses contain oily ingredients that start to smell like stale cooking oil over time, according to Dubroff, who also says to look out for changes in texture. "You'll know a lipstick has gone bad when it gets hard and you can't spread the pigment on your lips; lip gloss will feel streaky and globby if you try to apply it."
tips：唇部用品1年更換一次。當(dāng)唇油散發(fā)出不新鮮的烹飪油味道就說明已變質(zhì)。

Nail Polish 指甲油
Nail polish may just be the Twinkie of the beauty world: It won't go bad from bacteria. Eventually though, lacquer will dry out and become thick and clumpy, with the pigments settling along the bottom of the bottle. Shake it, and if the formula remains separated, it's done-zo.
tips：指甲油不會(huì)滋生細(xì)菌，但是時(shí)間一長(zhǎng)會(huì)干。如果搖晃之后，沉淀和油狀還是分離態(tài)，就變質(zhì)了。